Begin by washing and peeling the russet potatoes. Cut them into approximately 1-inch cubes. Rinse the cut potatoes in cold water to remove excess starch, then drain and pat them dry with a clean kitchen towel.
In a large skillet, heat the olive oil and 4 tablespoons of salted butter over medium heat. Allow the butter to melt completely and start to bubble, but be careful not to let it brown.
Once the butter is melted, add the diced onion and minced garlic to the skillet. Sauté for about 2-3 minutes until the onions are translucent and fragrant, stirring occasionally to prevent burning.
Carefully add the cubed potatoes to the skillet. Stir to coat them in the butter and aromatics. Spread them out evenly in a single layer to ensure they cook evenly.
Sprinkle the cayenne pepper, garlic powder, onion powder, and Season-All salt over the potatoes. Toss to coat the potatoes in the spices evenly.
Cover the skillet with a lid and let the potatoes cook for about 10 minutes. After 10 minutes, remove the lid, stir the potatoes, and add the remaining 2 tablespoons of butter.
Continue cooking the potatoes uncovered for another 10-15 minutes, stirring occasionally to ensure they crisp up evenly.
Once the potatoes are crispy and tender, remove them from the heat. Sprinkle the chopped parsley over the top for a fresh finish and serve immediately.
